In the field of information recording and reproducing devices for recording and reproducing data such as moving images or sounds, there have been developed information recording and reproducing devices including mountable/dismountable recording media such as optical discs, and optical disc drive devices for handling the recording media. As recording media for storing data for a long period, the optical discs are paid attention to.
It is true that optical discs are excellent recording media for storing data for a long period. However, in the case where data is recorded and stored in optical discs, several problems are involved resulting from deterioration of the optical discs and the optical disc drive devices.
Firstly, a recording mark formed on an optical disc may be deteriorated due to a storage environment or a usage condition, which may cause deterioration of the quality of a signal reproduced by an optical disc drive device. In a worst case, it becomes impossible to read out the recorded information. This is a problem called deterioration of recorded data in an optical disc. Further, deterioration of a recording film of an optical disc makes it difficult to form a recording mark, which makes it difficult to record data. In a worst case, it becomes impossible to secure a recordable state of an optical disc, from which a reproduction signal of a quality reproducible by an optical disc drive device is obtained. This is a problem called deterioration of the recording performance of an optical disc.
Further, in an optical disc drive device, deterioration of characteristics of a laser, adhesion of dust, deterioration of a transmission path for transmitting a reproduced signal, and deterioration of a spindle motor for rotating an optical disc may occur depending on a storage environment or a usage condition. In such a case, in spite of the fact that a recording mark is formed on an optical disc, which is reproducible by an optical disc drive device not deteriorated without a problem, the quality of a reproduction signal, reproduced by a deteriorated optical disc drive device, may be deteriorated. This is a problem called deterioration of the reproducing performance of an optical disc drive device. Further, it may become impossible to accurately form a recording mark by an influence such as deterioration of characteristics of a laser or deterioration of a transmission path for transmitting a recording signal, regardless of a fact that an optical disc is not deteriorated. This is a problem called deterioration of the recording performance of an optical disc drive device.
There are proposed several countermeasures against the aforementioned problems.
As a method for detecting deterioration of an information recording and reproducing device, there is proposed a method for detecting deterioration of the reproducing performance of an information recording and reproducing device by providing a reflection surface for detecting a reflection light amount of a laser in a drive device, and by detecting deterioration of the laser based on a change in the reflection light amount (see patent literature 1).
Further, as a method for detecting deterioration of an information recording and reproducing device, there is proposed a method for detecting deterioration of the recording performance of an information recording and reproducing device by preparing a reference medium, recording test data in the reference information recording medium, and detecting the number of spare sectors used at the time of reproduction (see patent literature 2).
Further, as a method for detecting an influence of dust, which is one of the factors of deterioration of an information recording and reproducing device, there is proposed a method for detecting an influence of dust adhered to an objective lens by providing a cartridge, including a light source and a light receiving element, for detecting dust, and by comparing a light amount of light emitted from the light source with a light amount detected by the light receiving element (see patent literature 3).
Further, as a method for detecting deterioration of the reproducing performance of an information recording and reproducing device, there is proposed a method including: calculating a quality value of a reproduction signal based on a correction condition in performing a Viterbi decoding process of the reproduction signal obtained by reading out predetermined data; and determining whether the reproducing performance of an information recording and reproducing device is deteriorated based on a change in the quality value (see patent literature 4).
Further, as a method for detecting deterioration of the recording performance of a recording medium, there is proposed a method for detecting deterioration of the recording performance of a recording medium by detecting a change in the error rate of recorded/reproduced data (see patent literature 5).
Further, as a method for detecting deterioration of data recorded in a recording medium, there is proposed a method for detecting deterioration of data recorded in a recording medium, with use of a change in the error rate detected by reproducing data in a predetermined area, a reproduction time, or the number of times of reproduction (see patent literature 6).